Very little is known about Bison (Vega in the Japanese version). Except that he is the head of Shadowlaw. In contrast to Ken and Ryu's Hadou (which is based in chi), Bison's powers are based in his rage and hatred, and are referred to as his "Psycho Power." Usage of his "Psycho Power" usually causes him to lose his ability to reason, and in one instance nearly strangles Chun Li while enraged only to regret his actions for a moment when he resumed his previous cognitive state... the only scene in which he ever shows a capacity for human emotion. As the leader of the secretive Shadowlaw, his only known goal is world domination, and most of his activities are financed through a variety of underground operations such as the Ashura syndicate. For all of Bison's power and ambition, it is suggested that much of his work may be the result of semi-telepathic influence originating from a silver idol in the form of an eagle's head, which is shown on at least two occasions to "communicate" with him.

(Source: Wikipedia)